In the design of ball valves, or like valves having rotatable valve elements, polymeric or synthetic material valve seats are typically provided. This is due partly to the fact that temperature differences in the valve causes differential thermal expansion of component parts of the valve, which can cause the ball to become enlarged and to jam if the seats are unyielding. Polymeric and synthetic material seats are yielding, whereas metal seats typically are not. Therefore, the design of metal seated ball valves is more complex.
Metal seated ball valves have a number Of advantages over synthetic material seated ball valves, and the like, if the problem of jamming as a result of differential thermal expansion, and related problems, can be avoided. For instance metal seated ball valves are able to much more effectively provide tight shutoff even if solids are present in the fluid being valved. Also, compared to synthetic material-seated valves, metal seated ball valves seldom require replacement or maintenance of the seats.
According to the present invention, a metal seated ball valve, or the like, is provided which can provide tight shutoff in the closed position (even if solids are present in the fluid being valved) without being subjected to jamming due to differential thermal expansion. The valve according to the present invention can provide tight shutoff in both directions, and is simple and inexpensive to construct.
The valve according to the present invention includes as major components thereof a valve body, a rotatable valve element, sealing means, and biasing means.
The valve body preferably is a metal body including means defining a through-extending bore therein (including first and second openings at opposite ends thereof) and an interior cavity.
The rotatable valve element preferably comprises a ball, and has a through-extending passageway therein. It is mounted for rotation about an axis for movement between a first, open position in which the passageway and the bore are generally aligned, to a second, closed position in which the passageway and the bore are not aligned. The ball may include trunions, a shaft, or like components, associated therewith.
The sealing means that are provided are mounted by the valve body adjacent the first end of the body and are for sealingly engaging the valve element and preventing flow of fluids through the bore first end when the valve element is in its second, closed position. The sealing means, or seat, may comprise a detachable metal sealing ring, or it may comprise sealing surface (e.g. a spherical machined surface) of the metal valve body.
The biasing means are particularly suited for effectively, simply, and inexpensively performing their function. The biasing means comprises a pair of elongated flexible linear spring elements spaced from each other along the axis of rotation, and operatively engaging the valve element adjacent the axis of rotation, and operatively engaging the valve body at positions spaced from the axis of rotation, and bias the valve element into sealing relationship with the sealing means. The elongated spring elements preferably comprise metal bars or rods which, at central portions thereof, operatively engage a groove formed in the valve element. A pin may be provided associated with each end of each spring element, each pin extending outwardly from the valve body and having a lost motion connection with the spring element. Additionally, the spring elements may make tangential line contact with a shelf portion of the body adjacent the pins. Further, the spring elements may have a bearing material portion connected at a central portion thereof for actually and operatively engaging the valve element.
It is the primary object of the present invention to provide a simple yet effective metal seated valve with rotatable valve element. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.